1. Field of the Invention
The present invention relates to a test apparatus and to a method of observing a biopsy specimen sampled by using the test apparatus. In particular, the present invention relates to a test apparatus for sampling a biopsy specimen from living tissue that can be used for making a pathological sample and for histopathological examination, and to a method of observing a specimen sampled by using the test apparatus.
2. Description of the Related Art
In medical institutes and hospitals, naked-eye observation of living tissue and observation of living tissue using an optical microscope or an electron microscope are widely performed.
In particular, pathological diagnosis is an important medical activity for determining the presence, the type, and the state of a lesion. In pathological analysis, a tissue specimen is sampled from a patient for whom cancer, a premalignant condition, or the like is suspected, and the tissue specimen is histopathologically examined by microscopic observation.
In order to reduce physical strain and mental strain on a patient, it is required that sampling of a specimen be minimally invasive and a diagnostic result be obtained in a short time by starting observation of the specimen as early as possible.
For example, needle biopsy has been increasingly used as a method for making pathological diagnosis less invasive. Biopsy is a procedure in which a part of body tissue of a patient, which will be used as a specimen, is sampled in order to diagnose or screen a disease.
In the following description, a method of using a needle for sampling a biopsy specimen will be referred to as “needle biopsy”, and a needle used for needle biopsy will be referred to as a “biopsy needle”.
Examples of biopsy needles include a hollow single-tube needle, a needle including an outer tube and an inner tube, and a needle including an outer tube and an inner needle. Each of the biopsy needles includes a cutter for cutting tissue and a specimen holder.
Sampling of a specimen by needle biopsy has been widely used recently because diagnostic information equivalent to that of surgical biopsy can be obtained less invasively by needle biopsy.
With such a method, even tissue that is located in a deep portion of the body of a patient can be percutaneously sampled, as described in British Journal of Cancer 82, 1017-1021, 2000.
Making specimen sampling less invasive provides, for example, the following advantages: reducing patient recovery time, reducing pain, reducing surgery time, reducing cost, reducing the risk of impairing adjacent body tissue, and suppressing damage to the anatomical appearance of a patient.
Examples of a method for reducing the time required for processing a specimen, which are under study, include techniques for observing an unstained tissue specimen. Nature Photonics 6, 845-851, 2012 describes a method of obtaining an image of an unstained tissue by slicing tissue removed from a living body in a frozen state, making a specimen by clamping the sliced tissue between two flat glass plates, and by observing the specimen using a stimulated Raman microscope.
Stimulated Raman scattering, which is a third-order nonlinear optical effect, is a phenomenon in which the energy of light having a shorter wavelength shifts to light having a longer wavelength when the light of the two wavelengths and molecular vibration of molecules interact with each other and the difference in the wavelengths of light coincides with the frequency of the molecular vibration. By using a stimulated Raman microscope, a signal generated due to stimulated Raman scattering caused by a specific molecular vibration of molecules in a specimen can be detected and the signal can be displayed as a contrast image. In other words, with such a system, an image representing information of the shape and the composition of a tissue specimen can be presented to a user without performing a staining process, such as hematoxylin and eosin stain or special stain.
Reduction in specimen processing time provides, for example, the following advantages: reducing or eliminating mental strain on a patient caused by the length of time before a diagnostic result is provided to the patient, which is mainly due to the time required for specimen processing; and reducing cost.
Examples of another method for reducing the specimen processing time include a combination of a specimen sampling method and a technique for observing an unstained tissue specimen.
For example, PCT Japanese Translation Patent Publication No. 2002-524780 describes a system for obtaining a tissue image by using a transparent trocar as a specimen sampling apparatus and as a tissue observation cassette.
With this system, a specimen of tissue is encapsulated in a transparent cassette while the specimen is being cut off the tissue by using a trocar, and an electro-optical imaging device is used. Therefore, it is possible to observe an unstained tissue specimen while considerably reducing the time required for sampling and processing the specimen.
However, even with the existing methods described above, it is still difficult to make specimen sampling less invasive while reducing the specimen processing time, and these methods have the following problems.
With the needle biopsy method described in British Journal of Cancer 82, 1017-1021, 2000, the time required for performing the entire procedure is not particularly reduced, although this method is effective in making specimen sampling less invasive.
In other words, with this method, the time required for processing a sampled specimen into a microscope specimen is considerably longer than the time required for specimen sampling and diagnosis. Therefore, even if the specimen sampling time is reduced by omitting incision and closure, the effect on the entire procedure is small and the time required for the entire procedure cannot be reduced considerably.
For example, in order to make a tissue specimen used for final diagnosis, it takes about 24 to 72 hours to perform a plurality of steps including chemical fixation, embedding, slicing, fixing to an observation substrate, and staining.
With the system described in Nature Photonics 6, 845-851, 2012, it is necessary to sample a specimen by cutting and slicing tissue in order to observe a specimen that is not located at a position that can be observed in vivo from the body surface or from the inside of a tubular organ.
Therefore, although the specimen processing time can be reduced by omitting a staining process, the time required for retrieving a specimen from a biopsy apparatus and the time required for slicing the specimen cannot be reduced. As a result, the method has a problem in that the effect of reduction in the total time for obtaining a diagnostic result is limited. Moreover, improvement of invasiveness of specimen sampling is not mentioned at all.
The system described in PCT Japanese Translation Patent Publication No. 2002-524780 has a problem in that the system is highly invasive as a means for specimen sampling.
A trocar, which is a surgical device that is used to insert another surgical device into a body cavity, is used by penetrating a sharp end of an obturator through a body wall and by leaving a hollow cannula, from which the obturator has been removed, in a retracted portion. A trocar has comparatively large outside diameter and inside diameter so that the other surgical device can be smoothly inserted.
With a general biopsy needle, which has an outside diameter less than 5 mm and mostly about 2 mm, strain on a patient can be minimized by removing the biopsy needle soon after the specimen has been sampled. In contrast, strain on a patient is considerably large when a trocar is used as a specimen sampling device.